Gaseous electric discharge device



Dec. 21, 1937. G DORGELQ 2,103,030

GASEOUS ELECTRIC DISCHARGE DEVICE Filed July 10, 1936 INVENTOR EduardGerardus Dorelo AT ORNEY Patented Dec. 21 1937 PATENT OFFICE -GASEOUSELECTRIC DISCHARGE DEVICE I Eduard G. DorgelmEindhoven, Netherlands, as-

signor to General Electric Company, acorpo:

ration of New York a Application July 10, 1936, Serial No. sass;

- In Germany July 19, 1935 3 Claims.

The present invention relates to gaseous electric discharge, devicesgenerally and more par ticularly the invention relates to starting andoperating circuits for such devices.

Gaseous electric discharge devices, such as electric discharge lamps,are successfully started into operation by a circuit comprising a choke'coil connected in series with the device across the terminals of analternating current source and an 10 electromagnetic switch actuated bythe series choke coil which switch, when closed, short circuits saiddischarge lamp. When potential is applied to a circuit of this type theswitch is moved from its closed position to its open circuit posi- 15tion by the current flowing through the choke coil. A voltage surge isthus produced in the choke coil which surge is applied across theterminals of the lamp to start the discharge therein. When the dischargehas been started the discharge current flows through the choke coil andthe switch is held thereby in its open circuit position to interrupt theoperation of the starting apparatus. When, however, the discharge doesnot start in the lamp the switch falls back to its closed cir- 5 cultposition, in which position the lamp is short circuited, and the abovedescribed operation in the starting apparatus is repeated. When the lampis inoperative so that it cannot be started by the starting apparatusthe apparatus continues 30 to operate. This is detrimental to the lifethereof, for example, the contacts of the switch may become fusedtogether, or the continual make and break of the switch in the startingapparatus causes radio disturbances.

35 Other types of "starting devices have similar disadvantages, forexample, for gaseous electric discharge devices comprising liquidmercury electrodes the starting apparatus frequently comprises means totilt the device to bring the elec- 40 trodes into momentary contact tocause the discharge to start therebetween. The operation of suchstarting means can be interrupted when the discharge device refuses tostart after an app'reciable time by a bimetallic switch which is 45traversed and heated by an electric current during the operation of thestarting apparatus. Such a device requires a complicated andexpensiveholding device to retain the bimetallic switch in its opencircuit position when the starting apparatus 50 has been open circuite'dthereby. Were such a holding means omitted-the starting apparatus wouldresume operation when the bimetallic switch had cooled sufficiently toclose the start in! circuit.

e object of the present invention is to provide a simple, inexpensiveand effectivemeans for interruptingthe operation of a starting apparatusof a gaseous electric discharge device, which apparatus automaticallyceases operation on the starting of'said device, when said device 5fails to start at a predetermined time after potential is appliedthereto. Further objects and advantages attaching to the device and-toits use and operation will be apparent to those skilled in the art fromthe following particular description.

The invention attains its object by associating with the startingapparatus a fuse having a high positive thermal coefficient ofelectrical resistance which fuse is traversed by current during theoperation of the starting apparatus and which, when heated to apredetermined temperature, breaks to open circuit said startingapparatus. When potential is applied to the startingapparatus andcurrent is flowing through the fuse the 6 temperature of the fuse atfirst is low and saidfuse offers but slight resistance to the flow ofcurrent therethrough. When the gaseous electric discharge device failsto start and the starting apparatus continues to operate the temperatureof the'fuse is gradually raised by the flow of current therethrough andthe resistance thereof gradually increases. The gradual increase in theresistance of the fuse to the electric current increases the temperaturethereof until the melting temperature of the fuse is reached at whichpoint the fuse breaks to cut the starting device out of circuit. Whendesired, the fuse is designed to break at a predetermined time afterpotential is applied to the starting apparatus which is not possiblewith the ordinary fuses having a thermal coeflicient of electricalresistance practically equal to zero.

Preferably the fuse consists of an iron wire mounted in a sealedcontainer having hydrogen or air therein. Such devices are now availablein commerce and are generally known in the electrical art as currentvariators." When desired, the fuse used in accordance with the presentinvention is small in size and is easily mounted in the lamp unit..

In the drawing accompanying and forming part of this specification agaseous electric discharge device and a starting and operating circuittherefor embodying the invention are shown schematically.

Referring to the drawing i is a gaseous electric .disch' rge device,such as a sodium vapor discharge lamp of the positive column typecomprising a sealed tubular container having electrodes which areelectron emitting when heated, a starting gas, such as neon or argon,and a quantity of vaporizable material, such as sodium, therein. Saiddevice I is connected in series with a choke coil 2 across the terminalsof an alternating current source 3 by the switch I. A fuse 6 consistingof a glass bulb having an iron wire sealed therein and containing a gasfilling, such as hydrogen or air is connectedacross the terminals of thedevice I by the lead 4. An electro-magnetic switch 5 actuated by thecurrent. flow through said choke coil 2 is connected into said lead 4.Switch 5 is in its closed circuit position when no current flows throughsaid choke coil 1, When a current of sumcient magnitude flows throughthe choke coil 2 switch 5 is moved thereby into an open circuitposition. 4 v

The gaseous electric discharge device I is started into operation byclosing the switch I. Current then iiows through the choke coil 2, theswitch 5, lead 4 arid the fuse 6, the gaseous electric dischargedevice'being short circuited when switch 5 is in its closed position.The current flow through the choke coil 2 moves the switch 5 to its opencircuit position which causes a voltage surge in the choke coil 2 whichsurge is impressed across the terminals ofthe device I to start thedischarge therei'n'. When the discharge starts in said device I theswitch 5 is held in its open position by the discharge current flowingthrough the choke coil 2 and the starting apparatus automatically ceasesoperation. When the discharge does not start in-the device. I the switch5 drops back to its closed circuit position and the above describedoperation'of the starting apparatus is repeated. The starting apparatuscontinues to operate until the device I is started or untilthe iron wirein the fuse 6 is heated to. its melting temperature by the currenti'flowtherethrough. When this-temperature is reached the iron wire I breaks tointerrupt the flow of current through a the starting apparatus. Thecircuit is then inoperative until the fuse 6 is replaced at which timethe defective discharge device I is either repaired or replaced.

The device described above is of simple ethieture, is effective inoperation andthe starting apparatus has along useful operating life.

While I have shown and described a particular device embodying myinvention it will be understood of course that numerous changes in theform and details, of the device and in its use and operation may be madeby those skilled in the art without departure from the spirit and scopeof the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is? 1. In combination an electric discharge device, an automaticstarting-means which ceases operation on the starting of said deviceconnected in series therewith and a fuse consisting of a metal wirehaving a high positive thermal coefdcient of electrical resistanceenclosed by a sealed container having gaseousatmosphere therein, saidfuse being connected in series with said starting means and across theterminals of said device to interrupt current flow through said startingmeans on the failure of said discharge device to start at apredetermined time after potential is applied to said device.

2. In combination an electric discharge device, an automatic startingmeans which ceases operation on the starting of said device connected inseries therewith and a fuse consisting of an iron wire enclosed by asealed container having a hydrogen containing gas therein, said fusebeing connected in series with said starting means and across theterminals of said device to interrupt current flow through said startingmeans on the failure of said discharge device to start at apredetermined time after potential 'is applied to said device. I

v 3. In combination a gaseous electric discharge device, an automaticstarting means which ceases operation on the starting of said deviceconnected in series therewith and .a fuse having a high positive thermalcoefflcient of electrical resistance connected in series with saidstarting means and across the terminals of said device to interruptcurrent fiow through said starting means on the failure of saiddischarge device to start at a predetermined time after potential isapplied to said device.

' EDUARD G. DORGELO.

